P C / 1 0 4 C P U M o d u l e P F M - 5 4 0 I R e v . BChapter 2 Quick Installation Guide 2 - 167 RTS 8 CTS9 RI/5V 10 N.C2.20 COM3 Connector (CN11)Pin Signal Pin Signal1 DCD 2 RXD3 TXD 4 DTR5 GND 6 DSR7 RTS 8 CTS9 RI 10 N.C2.21 Power Connector (CN12)Pin Signal1 +5V2 GND3 GND4 +12V2.22 COM 2 Connector (CN13)Pin Signal Pin Signal1 DCD(485/422_TX-) 2 RXD(422_RX+)3 TXD(485/422_TX+) 4 DTR(422_RX-)5 GND 6 DSR7 RTS 8 CTS